1. Field
The present disclosure relates generally to aircraft and, in particular, to controlling movement aircraft. Still more particularly, the present disclosure relates to a method and apparatus for reversing thrust in an aircraft using a thrust reverser system.
2. Background
When a typical commercial or military sized aircraft lands, the passenger aircraft may land at a speed from about 140 mph to about 160 mph. These aircraft may weigh from about 80,000 pounds to over 800,000 pounds. Reducing the velocity of an aircraft of these weights and at these speeds may be challenging. Therefore, these aircraft typically require robust systems that can handle the force of slowing down and stopping the passenger aircraft.
When an aircraft lands, reducing the speed of the aircraft to bring the aircraft to a stopped position may involve many different mechanisms. In stopping the movement of an aircraft after landing, one type of system used to reduce the speed of the aircraft is a landing gear system. These landing gear systems use breaks to slow down the aircraft. The aircraft brakes are designed to absorb large amounts of energy to reduce the speed of the aircraft.
Control surface systems may be used to reduce the speed of the aircraft after landing. For example, ground spoilers may be deployed after the aircraft lands to slow down the speed of the aircraft.
Another system used to reduce the speed of an aircraft involves changing the direction of thrust in the jet engines in the aircraft. Thrust reverser systems are employed on engines to change the direction of thrust. In particular, the direction of thrust is changed from a direction aft of the aircraft to a direction toward the front or forward part of the aircraft.
Thrust reverser systems may include sections such as sleeves that open at the rear of an engine. With a thrust reverser system, a sleeve covering cascades may be moved in an aftward direction. The cascades are an array of structures that direct airflow in an engine. These cascades, when exposed, may direct airflow out through the side of the engine and in a forward direction rather than the airflow flowing in an aft direction out of the engine.
Additionally, when the sleeve is moved, blockers or other structures also may block the opening through which the exhaust typically flows out of the engine. These blocking structures along with the cascades may direct air in the forward direction to reduce the speed of the aircraft.
These sleeves and other components are typically moved using hydraulic systems, motors, actuators, valves and plumbing components that add undesired weight and complexity to the aircraft. With the number of components used to move the sleeves, maintenance may be more time consuming and expensive than desired. Also, the aircraft and the engine may weigh more and may be more expensive to manufacture than desired.
Therefore, it would be desirable to have a method and apparatus that improves at least one of the issues discussed above as well as possibly other issues.